Stove construction



Nov. 11, 1941. R. c. SABINS STOVE CONSTRUCTION Filed April 6, 1940 4Sheets-Sheet l 7 JNVENTOIR. 1202mm 6 fiabuw.

Nov. 11, 1941. R. c. SABI NS 2,262,254

I STOVE CONSTRUCTION Filed April 6, 1940 4 Sheets-Sheet 2 INVENTOR.

labile/4d C. alxrze M11, 1941 R. c. SABINS 2,262,254

STOVE CONSTRUCTION Filed April 6, 1 940 4 Sheets-Sheet 3 fiollarzd C5abuz5,

n- A i INVENTOR.

4 Sheets-Sheet 4 i l 1 a BY 1 l R C SABINS STOVE CONSTRUCTION FiledApril 6, 1946 Nov. 11. 1941.

Patented Nov. 11, 1941 UNITED STATES PATENT OFFICE STOVE CONSTRUCTIONRolland C. Sabins, Wisconsin Rapids, Wis.

Application April 6, 1940, Serial No. 328,300

4- Claims.

This invention relates to a new and improved stove construction and moreparticularly to a new and improved draft regulator and control forstoves.

While the improved regulator and controlis adapted for general use inconnection with stoves of different types, it is especially adapted foruse in connection with space heating stoves employing pot type burners.

Space heating requires a stove which may be adjusted to low or moderateheats as well as to high heats and which will operate efliciently over aconsiderable range of heat adjustment. With pot type burners the heatadjustment is made solely by controlling the flow of fuel to the burner.It is found in practice, however, that agiven burner requires much lessdraft for efilcient operation at a low fuel setting than it does for ahigh fuel setting. While dampers adapted to cut the effective draft onthe burner by admitting room air to the stack or flue, may operateefficiently with regard to combusition they reduce the overall heatingefficiency of the stove or heater. This is for the reason that the airadmitted to the flue through the damper is heated room air which must bereplaced by cooler air drawn into the room by the draft. The use of suchdampers for continuous draft control is therefore undesirable. Dampersof this type are suitable for intermittent operation to take care oftemporary variations in draft conditions.

Dampers which operate to partially obstruct the flue opening serve toreduce the effective draft at the burner without admitting room air tothe flue. This type of damper requires initial adjustment to take careof normal stack draft and requires adjustment with variations in thedraft. For example, tests show that with a given stack or ofitake fluearrangement the effective draft may be substantially doubled with a dropof twenty degrees in outside temperature. Provision should be madetherefore to permit draft adjustment to maintain substantially the sameeffective draft at the heater regardless of changes in barometric andtemperature conditions.

In addition, the draft must be varied with the input of fuel to the pottype burner, if the burner is to operate efliciently at differentsettings. The draft required varies with the heat output of the burnerand consequently the draft adjustment for different fuel settings can bethermostatically controlled.

It is an object of the present invention to provide a new and improveddraft control for stove constructions.

It is a further object to provide a draft control which may beadjustable to compensate for variations in external draft conditions andis automatically adjustable to take care of variations in draftrequirements within the stove or heater.

- trol housing 2!.

It is an additional object to provide a damper control which isthermally adjustable and which is adapted for coaction with a controlresponsive to relative pressures in the dues and areas adjacent thereto.

It is a further object to provide controls of this character which serveto vary the effective area of the flue leading from the stove or heater.

It is also an object to provide a draft control which is simple indesign, composed of but few parts and adapted for commercial productionand use.

Other and further objects will appear as the description proceeds.

I have shown certain preferred embodiments of my invention in theaccompanying drawings, in which Figure 1 is a side elevation with partsbroken away, showing a stove with the invention incorporated therein; v

Figure 2 is a fragmentary view on an enlarged scale showing the damperconstruction of Figure 1;

Figure 3 is a view 'of Figure 2 as seen from the Figure 4 is a viewsimilar to Figure 2 but showing a modified form of damper construction;

Figure 5 is a rear face view of the damper construction of Figure 4Figure 6 is a cross-section of a modified form of damper construction;

I Figure 7 is a section taken on line of Figure 6; .and 1 Figure 8 is asection taken on line 8-8 of Figure 6.

Referring first to the form of construction shown in Figures 1, 2 and 3,in Figure 1 is shown a space heating stove comprising a housing llenclosing a heating drum l2. The pot type burner I3 is supported frompartition il in the drum l2, air for combustionentering through theopening IS in the base .l6 of the drum. Fuel is contained in tankv l1and is supplied to the burner l3 through the constant level valve I8 andpipe IS. The drum I2 is provided with the open ing 20 for the dischargeof products of combustion, this opening discharging into the draft con-The housing 2| is provided with the smoke pipe connection 22 forconnection to a flue or chimney for discharge of the products ofcombustion.

As best shown in Figure 2, the upper portion of the rear wall of thedraft control housing 2! carries the .draft control vane 23, supportedon a transverse pivot at 24. This pivoted vane type of control isdisclosed in my copending application Serial No. 256,448, filed February15, 1939. The vane 23 has a bi-metallic strip 25 secured thereto, thestrip adjustably supporting the weight 26, which may be moved toward oraway turned end 53.

cured to the end 53 of the control rod 50 and from the vane by rotationof the knob 21. The fixed deflecting plate 28 serves to keep the directflow of products of combustion away from the vane 23 and also causes thevane to be less responsive to slight momentary draft fluctuations.

The manual control rod 38 is provided with knob 3| and slides in alignedopenings in the wall of the housing II and of the drum l2. This rod 30carries the downtumed lug 32 to which is secured the bi-metallic strip33 having the damper support 34 fastened to its lower end. The vanesupport 34 carries the disc damper 35 which, as shown in Figure 3, iscentered in the opening 20in the drum l2. The size of the damper 35 ispreferably so related to the size of the opening 28 that the dampercovers appro matelv eighty percent of the flue opening when the damperis in its fully closedposition.

The form of construction shown in Figures 4 and 5 differs from that ofFigures 1 to 3 in the construction and support of the adjustable vanefor the flue opening. The manual control rod is provided with knob 5|and with the downturned inner portion 52 having the out- The damperframe 54 .is secarries the supports 55 for the thermostatic strips 56.The opposite ends of the strips 56 have the connecting members 51fastened thereto, these connecting members having pins 58 fitting inopenings in the damper supports 59 which carry the damper 50. Thecombined areas of the openings between damper frame 54 and the drum l2and between the damper 60 and the damper frame, with the parts in theclosed position, are preferably approximately twenty percent of the fullarea of the outlet flue openin The form of construction shown in Figures6 to 8, inclusive, differs from those of Figures 1 to 5 in that thedamper and control construction is located in connection with the flueor smoke pipe rather than directly associated with the heating drum anddraft control housing. The

pipe section has the lateral opening 66 formed damper frame I8 alsocarries the stops 85 adapted to engage the face of the damper 84 andlimit its movement in one direction.

The form of construction shown in Figures 1 to 3 includes both aswinging barometric control damper-and a damper located in such positionas to vary the effective area of the oflftake flue leading from thecombustion chamber or heating drum. The manual control rod 3fl serves tomove the damper 35 away fromand toward the discharge opening. Thisdamper as is of such area that the damper and its support when in theposition to afford the maximum obstruction to products of combustionstill leaves available twenty percent of the cross-sectional area of astandard flue pipe. percent flue area is required by the underwriterslaboratories in their limitations as to the use of a damper device of acharacter tending to obstruct the flue pipe.

. The manual adjustment of the rod 30 will depend upon the effectivedraft afforded by the flue and stack. For example, if with the rod 38 atits innermost position, leaving the flue opening entirely unobstructed,a draft gauge placed in an opening in the combustion chamber wall ordoor indicates a draft reading of .15 inch and a firebox draft of.08'inch is desired, the operator would move the control rod 30outwardly to restrict the outlet for the products of combustion to suchan extent that the firebox draft as indicated on the draft gauge reachedthe desired reading of .08 inch. During this procedure of adjustment thebarometric draft control 23 is held in the closed position.

After th proper adjustment for the damper 35 has been found, thebarometric draft control is released and the weight 26 is adjusted sothat the vane 23 teeters in a closed position. With.

this barometric draft control vane 23 so adjusted, it will react tomomentary draft increases and yet will not continuously draw heated roomair out through the stack. At the same time, by

the vane housing 68 below and behind the barometric vane 59. The housing68 contains the limiting stops 18 and 1| for limiting movement of thevane 69 in opposite directions. The vane 59 is positively connected tothe rotatable cross shaft 12 which shaft, as shown in Figure 6, carriesthe counterweight 13 adapted to counterdamper body being supported'bythe short shaft- 19. The outer end of the shaft section 19 carries thegrooved arcuate member 88 to which is secured one end of the chain 8|.This chain lies in the groove in member 80 and has the adjustable draftcontrol weight 82 fastened to its free end. The-member 80 and the chainsupport for 'the weight 82 afford that weightia constant lever armregardless of the rotary position of the shaft 19 and the damper frameI8.

The damper frame 18 has one end of the bi-metallic strip 83 secured .toit, the other end of the strip supporting the damper 84. The

momentary operation as required by draft fluctuations, the firebox draftwill be held substantially constant. The adjustment procedure outlinedabove will be carried out with the metering valve of the heater adjustedat its maximum open position, with the burner therefor burning at itshigh fire setting. The high temperature of the products of combustionwill raise the temperature of the bi-metallic strip to 33 so as toswing'the damper 35 to the left, as seen in Figure 1, thus swinging itawayfrom the outlet opening and increasing the effective area of thatopening.

When it is desired to burn the heater at a lower flre setting, the fuelvalve is adjusted as desired. With a lower flame the heat of theproducts of combustion is reduced and' when they reach th bi-metallicstrip 33 they have less effect upon that strip. This causes the strip toreduce its curvature, which serves to swing the damper 35 toward th flueopening. The damper being closer to the opening automatically reducesthe firebox draft. At the same time 'the reduced temperature alsoaffects the bi-metallic strip 25 on the barometric draft control vane 23and moves the weight adjustment in the outward direction in proportionto the temperature reduction. V

It will not be necessary to change the manual control rod '30 unlessthere is a substantial change in efiectivestack draft. 'I'Lis may becaused by a substantial drop in temperature This minimum twenty causedby variation in wind conditions.

outside the house or may b caused by wide variations in barometricpressure; or it may be In any event this change is comparatively seldomrequired and when made is effective for all burner settings. It will beunderstood that the ordinary user of the stove may not be provided witha draft indicator, but it is possible to reach an approximately correctsetting of the manual damper by observation of the flame and by check ofthe character and temperature of the products of combustion.

Referring next to the form of construction shown in Figures 4 and 5, theoperation is substantially the same as that which has been describedabove in connection with Figures 1 to ,3. In this construction threeseparate bi-metallic strips are provided so that the damper is not swungbut is moved along a line substantially normal to its surface. Thethermostatic elements operate in the same manner, however, to move thedamper away from the draft outlet under high temperature conditions andto retract it toward the outlet under low temperature conditions.

The form of construction shown in Figures 6 to 8 inclusive, operates inthe same general manner in that it serves to reduce the effective fluearea. It is not located immediately adjacent the combustion chamber,however, or in that chamber, as are the constructions of Figures 1 toinclusive. This form of construction is preferably placed in the fluepipe or stack several feet away from the stove or heater. Theconstruction shown provides a simple control by which a single damper isautomatically adjusted both thermostatically and by variations ofrelative barometric pressures. The damper 84 and its supportingbi-metallic strip 83 are so located that the damper is swung away fromthe damper body 18 under high temperature conditions to dampers in thconstructions of Figures 1 to 5.

The damper body 18, however, is also directly 1 moved by the barometriccontrol vane 69 which is positively connected to the shaft supportingthe damper body 18. It will be understood that this barometric vane 69is designed to substantially fill the cross-sectional area of itshousing 68. Therefore this vane does not in any position allow theentrance of any substantial amount of air into the flue. Thecommunicating chamber 61 merely transmits the pressure or draft in theflue below the damper body 18 to the rear of the barometric vane 69. Theopposite face of the vane is subjected to atmospheric pressure'of theroom in which the pipe is located. Therefore the movement of the vane69, in the absence of other factors,'is dependent on the relationshipbetween the draft in the flue and the barometric pressure in the room.

The vane is counterbalanced so that its own weight is not effective inany position to vary response to the difference in pressure upon itsopposite faces. The size of the opening behind the room intake airadjuster 15 may be varied to prevent too sudden movement of the vaneupon fluctuations in pressure. The adjustable draft control weight 02serves to place a load upon the barometric vane- 8, which load isvariable as desired, but which is constant weight to have a constanteffective lever arm regardless of the position of the vane. This'form ofconstruction, therefore, permits an initial adjustment which isdependent upon the effective draft in the stack and which reacts to thedifference in barometric pressure between the gases or air in the flueand the air in the room. In addition the damper 84 supported by therotating damper frame J8 serves to automatically adjust the effectiveflue opening upon variations in the heat of the products of combustionreaching its bi-metallic strip.

While I have shown certain preferred embodiments of my invention by wayof example, it is to be understood that it is capable of furthermodification and change to meet differing conditions and requirements,and I contemplate such modifications as come within the spirit and scopeof the appended claims.

' What is claimed is:

1. In a stove construction, a combustion chamber, a passage for productsof combustion leading from said chamber, a damper element within thecombustion chamber extending across the entrance to said passage, a heatresponsive mounting within the combustion chamber for said elementadapted to vary the position of said element upon changes oftemperature, a linearly adjustable support for the heat responsivemounting extending into the combustion chamber, and manually operablemeans for moving said support.

2. In a stove construction, a combustion chamber, said chamber having aport for products of combustion, a damper element within the combustionchamber extending across said port, and a heat responsive mounting forsaid damper comprising a bi-metallic strip extending parallel to theface of the damper within the combustion chamber whereby the damper isswung toward and away from said port upon variations in temperature.

3. In a. stove construction, a combustion chamber, said chamber having aport for products of combustion, a damper element within the combustionchamber extending across said port, a heat responsive mounting for saiddamper comprising a bi-metallic strip whereby the damper is swung withinthe combustion chamber toward and away from said port upon variations intemperature, an adjustable support for the heat responsive mounting, andmeans for adjusting the position of the adjustable support.

4. In a stove construction, a combustion chamber, said chamber having aport for products of combustion, a damper element extending across saidport, a heat responsive mounting for said damper whereby the damper ismoved toward and away from said port upon variations in tem-- perature,an adjustable support for the heat responsive mounting, means foradjusting the position. of the adjustable support, a sliding rodcarrying the heat responsive mounting. and a handle located exteriorlyof the stove for moving said sliding rod.

RQLLAND C. SABINS.

